def main():
    x = int(input())
    if x >= 30:
        print('Yes')
    else:
        print('No')

if __name__ == '__main__':
    main() def main():
    x = int(input())
    if x >= 30:
        print('Yes')
    else:
        print('No') main x = int(input()) x int(input()) int input() input if x >= 30:
        print('Yes')
    else:
        print('No') x >= 30 x 30 print('Yes') print 'Yes' print('No') print 'No' if __name__ == '__main__':
    main() __name__ == '__main__' __name__ '__main__' main() main def main():
    x = int(input())
    if x >= 30:
        print('Yes')
    else:
        print('No') def main():
    x = int(input())
    if x >= 30:
        print('Yes')
    else:
        print('No') main
def main():
    x = int(input())
    if x >= 30:
        print('Yes')
    else:
        print('No')

if __name__ == '__main__':
    main()